Adaptations to Extreme Environments

Abstract

The land masses of the world provide far more extreme and variable habitats than do the oceans. It is to such environmental extremes that terrestrial arthropods must become adapted if they are to survive. This they can do either behaviorally, avoiding the most severe conditions by retreating into crevices and holes, or by physiological means, or by both. Physiological adaptations may occur in some or all stages of the life cycle. The most extreme environmental conditions are sometimes resisted in a state of diapause (Sect. 6.6.1) or even in one of cryptobiosis (Sect. 6.6.2). Examples of physiological adaptation to extreme environments are afforded by the fly Psilopa petrolei which inhabits puddles of crude petroleum, feeding on the dead insects found there, and by the beetle Niptus hololeucus, which can live on cayenne pepper and thrive on sal ammoniac. This species has also been found inhabiting the corks of entomologists’ cyanide killing bottles. Tenebrionidae, including the mealworm beetle Tenebrio molitor, can live on dry food without drinking, although excessive dryness in a mealworm culture leads to cannibalism; while the larvae of carpet beetles, clothes’ moths and other arthropod pests of stored products can also do without free water completely.